Have you tried erasing the startup config?
router#erase start
then issue the command
router#reload
the router will then ask if you want to save any changes made. answer with "no" and then continue with the reload. That should take care of your problem. If not, then you might have to reload the IOS by TFTP.
or
I had this problem as well, turns out that when I had tried to reset the password I hadnt changed the config-register back to waht it sould be.
Try going into enable mode and then into config mode
Hostname (boot)(config)# or something like this and the type
Hostname(boot)(config)# config-register 0x2102
then Ctrl-C out of config mode and type reload
or
let it boot to router<boot>. then erase flash and nvram. reboot and go into rommon and issue the command "confreg 0x2102" then reboot
it will start in router<boot> again go ahead and configure the ethernet port on the router and then issue the command " copy tftp flash" put in the IP address of your tftp server, then type in the name of your IOS image: example- c1600-k8osy-mz.122-15.T16.bin .